The present invention relates generally to vision testers and vision testing methods, and more particularly to a novel system and method for testing visual sensitivity of a subject to contrast.
The present invention provides a compact, portable, and battery operated system comprising electroluminescent lighting and light sensors used in conjunction with suitable control and microprocessor units to provide a vision test for sensitivity to contrast of various display configurations. A beam splitter superimposes the images of a test pattern and a neutral background density filter, each of which is transilluminated by an electroluminescent panel. The relative luminances of the two panels provide a measure of contrast. The microprocessor unit calculates the contrast based upon readings of light sensors disposed near each electroluminescent panel. The method incorporating the vision testing system of the invention combines variable contrast patterns, such as sine wave or square wave patterns of various frequencies, tri-bar patterns and spot patterns, and variable spatial frequency test patterns comprising resolution fans.
It is, therefore, a principal object of the present invention to provide an improved vision tester and method for testing visual sensitivity to contrast.
This and other objects of the present invention will become apparent as the detailed description of certain representative embodiments thereof proceeds.